Bell's Reaper, 1827-1828.
© Science Museum / Science & Society Picture Library
This machine, designed by Patrick Bell (1799-1869), is believed to be the first practical mechanical reaper and has several features that were incorporated into early combine harvesters. The reaper has undergone various modifications during its working life, one of the most important being the replacement of a cutter based on scisors with a reciprocating knife mechanism. The crop was collected by a revolving frame (reel) onto an inclined apron which delivered the corn at the sides of the machine. The reaper was designed to be propelled by a single horse but this was found to be inadequate; it was modified so that two horses were used behind it. Steering in this later form was achieved by a driver holding a bar connected to the horse-pole.